1. Field of the Invention
This invention relates to an adjustable platform for a rung ladder.
Conventional rung ladders have a plurality of narrow parallel struts, generally of cylindrical form, which enable the ladder to be scaled when supported against the wall of a building for example. These rungs however, by virtue of their narrow form, tend to give rise to bodily discomfort if it is necessary to stand on the rungs for a prolonged period, also the small area of contact between the rungs and the users feet induce nervousness in some people.
It is an aim of the present invention to provide a platform for use with a rung ladder to avoid the aforementioned problem. As a ladder may be used at a range of inclinations to the horizontal, it is a further aim to provide a platform which can be positioned horizontally for that range of inclinations. A still further aim is to be able to locate the platform adjustably along the length of the ladder.
Accordingly the present invention provides an adjustable platform for a rung ladder comprising guides, a footplate and a footplate support system. Means is preferably provided for the footplate to releasably engage a rung of the ladder, and means is provided for clamping the footplate in a desired position. Conveniently, the clamping means comprises sliding clamping block slidably received in the guides and clamping units.
Two parallel guides are preferably provided and running lengthwise of the ladder, and may be purpose formed extrusions serving as styles for the ladder. Alternatively the guides may be configured to adapt an existing ladder, for example as extrusions to be bolted to styles.
To enable the angle of the footplate relative to the ladder to be varied in order to accommodate a range of angles of inclination of the ladder to the horizontal the footplate is movble relative to a position of the footplate support system. More particularly, the footplate is pivotably secured to a pair of support arms by way of pivot blocks. The support arms are pivotably secured at their other ends to the aforementioned sliding clamping blocks. A further pivotal connection of the footplate to the guide is preferably provided by way of two sliding blocks each received slidably in a respective one of the guides, and pivotably connected to respective associated pivot block carried by the footplate.
On an adjustable platform manufactured for an existing ladder means is provided for adjusting the footplate support system to suit ladders of different widths. Conveniently such adjustment may be effected by arranging for the aforementioned pivot blocks to be adjustably laterally by way of tee bolts and tee bolt guides.